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hugetlb: pull gigantic page initialisation out of the default path

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As we can determine exactly when a gigantic page is in use we can optimise
the common regular page cases by pulling out gigantic page initialisation
into its own function.  As gigantic pages are never released to buddy we
do not need a destructor.  This effectivly reverts the previous change to
the main buddy allocator.  It also adds a paranoid check to ensure we
never release gigantic pages from hugetlbfs to the main buddy.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>		[2.6.27.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andy Whitcroft
2008-11-06 12:53:27 -08:00
committed by Linus Torvalds
parent 69d177c2fc
commit 18229df5b6
3 changed files with 34 additions and 9 deletions
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30
mm/page_alloc.c
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@@ -263,34 +263,48 @@ void prep_compound_page(struct page *page, unsigned long order)
{
int i;
int nr_pages = 1 << order;
struct page *p = page + 1;
set_compound_page_dtor(page, free_compound_page);
set_compound_order(page, order);
__SetPageHead(page);
for (i = 1; i < nr_pages; i++, p++) {
if (unlikely((i & (MAX_ORDER_NR_PAGES - 1)) == 0))
p = pfn_to_page(page_to_pfn(page) + i);
for (i = 1; i < nr_pages; i++) {
struct page *p = page + i;
__SetPageTail(p);
p->first_page = page;
}
}
static void destroy_compound_page(struct page *page, unsigned long order)
#ifdef CONFIG_HUGETLBFS
void prep_compound_gigantic_page(struct page *page, unsigned long order)
{
int i;
int nr_pages = 1 << order;
struct page *p = page + 1;
set_compound_page_dtor(page, free_compound_page);
set_compound_order(page, order);
__SetPageHead(page);
for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
__SetPageTail(p);
p->first_page = page;
}
}
#endif
static void destroy_compound_page(struct page *page, unsigned long order)
{
int i;
int nr_pages = 1 << order;
if (unlikely(compound_order(page) != order))
bad_page(page);
if (unlikely(!PageHead(page)))
bad_page(page);
__ClearPageHead(page);
for (i = 1; i < nr_pages; i++, p++) {
if (unlikely((i & (MAX_ORDER_NR_PAGES - 1)) == 0))
p = pfn_to_page(page_to_pfn(page) + i);
for (i = 1; i < nr_pages; i++) {
struct page *p = page + i;
if (unlikely(!PageTail(p) |
(p->first_page != page)))